Writing often becomes difficult to read when the writer must stop to explain every point for a complete layman. Alternately, writing that lacks sufficient explanation can be impossible to understand.
In conversation, we use our other senses to alert us to whether we are communicating effectively. But in writing for a print audience, we have to make assumptions about that audience's level of knowledge and write accordingly. The inefficiency of this assumption is just comes with the medium.
We may make similar assumptions on the Web, but in general it is often better to link to explanations that do not themselves advance your argument toward its conclusion.